1. Field of the Invention
The present invention relates to an iron type golf club head which has improved directional stability of a hit ball by increasing the moment of inertia around the vertical axis which passes through the center of gravity of the head.
2. Description of the Background Art
Conventionally, in order to improve directional movement or a flight distance of a hit ball, various improvements have been made to an iron type golf club head. For example, a technology of using a light alloy c having low specific gravity, such as an aluminum alloy, proposes in a part of a hosel section b, as shown in FIGS. 7 (a) and (b). Since this technology reduces weight of an upper side of a head a, the center of gravity of the club head a can be lowered.
However, in the club head a as described above, as the mass on the heel side becomes small, the moment of inertia around the vertical axis passing through the center of gravity g1 of the head also becomes small. Such a club head a has had a problem that if a golfer hits a ball at a position which is off a sweet spot ss, an intersecting point of a normal oriented to a face d from the center of gravity g1 of the head with the face d, a hit ball is liable to veer.